The present invention relates to a sampling apparatus and, more particularly, to an apparatus for dispensing samples of liquids containing particulate matter or immiscible liquids.
A long standing problem with existing liquid sampling techniques is obtaining a representative sample of the original liquid when such original contains suspended solids, immiscible liquids, or other particulates. The problem results from the tendency of the particulate to settle to the bottom of or at any strata in the sampling container. When a portion of the liquid is withdrawn or poured off to assay for total solids or total specific metals or ions, the assay portion is typically not representative, and inaccurate results are obtained.
The usual method for dispensing the accumulated solids in the sampling container is to agitate the container and then pour off a small portion which, in turn, is again agitated before an aliquot is taken for analysis. The first separation step allows a disproportionate amount of solid particulate to remain in the container than in the small withdrawn portion. This is further compounded when the aliquot usually contains proportionately less particulate than is in the small sample. As more individual samples are withdrawn the particulate concentration per unit volume increases because of the inadequacies of the sampling technique.
These sampling problems are particularly acute in splitting samples of waste water and in obtaining aliquots of them. Standard samplers for waste water usually collect composite samples into ten-liter containers, or aliquots may be taken from small laboratory glassware. Currently there is no sample splitter design available which may be utilized in a broad range of sampling operations.
A further requirement for an effective sampling apparatus is simplicity of construction. A sampler must be capable of easy assembly and disassembly for cleaning purposes. Because any sampling results are adversely affected by contamination, the sampling apparatus must be thoroughly cleaned after each usage. In sampling waste water, particulate matter tends to adhere to container surfaces and lodge in complex valving. Difficulties in removing such particulate buildups on existing sampling apparatuses is well known. The present invention involves the use of an apparatus which is easily disassembled and made of polypropylene or other materials which may be coated to further reduce particulate buildup.